"If you ask me what are the possibilities of getting the IRA to put weapons beyond use, I can only say that task has been made much more difficult."

His comments were made against a backdrop of rising violence, with one policeman describing weekend riots in north Belfast as the worst violence the area had seen in 20 years. Fourteen police officers were injured and at least eight bombs were thrown as loyalists and republicans clashed.

According to local sources, shots were fired by both sides. At one point a Kalashnikov, the Provos' firearm of choice, was fired from the Roman Catholic side. Mr Adams hit out at Unionists and the British and Irish governments for focusing solely on the issue of IRA guns.

He described calls from John Reid, the Northern Ireland Secretary, for republicans to begin putting their weapons beyond use while loyalists attacked Roman Catholics in north Belfast as a "disgrace".

He added: "If those who are against the Good Friday agreement think they are going to break or bend the will of Irish republicans, then they are mistaken. I am making it clear that Sinn Fein will not and cannot be excluded from this process."

Mr Trimble, who needs 30 signatures to enable his exclusion motion to go ahead, met members of the anti-agreement Northern Ireland Unionist Party yesterday to persuade them to sign it. Cedric Wilson, the party's leader, said he would sign if the motion was tabled immediately.

But he added that Mr Trimble had agreed to a request from Tony Blair to delay his motion for three weeks while efforts were made to persuade the IRA to disarm. Mr Wilson said: "We want to see a motion on the floor of the House as soon as possible. There is no good reason it cannot be debated this week."

He accused Mr Trimble of trying to fudge the issue to allow for a "cosmetic" exercise on decommissioning. He added: "Mr Trimble could have every Unionist in this Assembly signing this motion if he said `let's do it now'."

Mr Reid said a resolution to the crisis engulfing the process was out of his hands. "Decommissioning is a voluntary act," he said. "Participation in the Executive is a voluntary act. I cannot force the parties to stay in government if the will is not there.

"That is the responsibility of Northern Ireland's politicians, working together to resolve their difficulties, to find the common ground. It is the challenge of the paramilitaries to put their words into action."